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The sperm move into the vas deferens, and are eventually expelled through the urethra and out of the urethral orifice through muscular contractions. However, most fish do not possess seminiferous tubules. Instead, the sperm are produced in spherical structures called sperm ampullae. These are seasonal structures, releasing their contents during ...
The vas deferens (pl.: vasa deferentia), ductus deferens ... As in cartilaginous fish, the upper part of the duct forms the epididymis. In many species, the vas ...
VD = vas deferens Head of a mating Helix pomatia showing the everted penis (P), and the dart sac (S) in the process of shooting a love dart (D). Head of Helix pomatia after mating with everted vagina (V) and penis (P). Pulmonate land gastropods are simultaneous hermaphrodites and their reproductive system is complex. It is all completely ...
The mesonephros persists and forms the anterior portion of the permanent kidneys in fish and amphibians, but in reptiles, birds, and mammals, it atrophies and for the most part disappears rapidly as the permanent kidney (metanephros) begins to develop [2] during the sixth or seventh week. By the beginning of the fifth month of human development ...
In a male, they develop into a system of connected organs between the efferent ducts of the testis and the prostate, namely the epididymis, the vas deferens, and the seminal vesicle. The prostate forms from the urogenital sinus and the efferent ducts form from the mesonephric tubules .
Tail end of human embryo, from eight and a half to nine weeks old. 1 - 7: Homologous male and female pelvic organs. Diagrams that show the development of male and female organs from a common precursor.
The caudal region of the reptilian epididymis, where sperm are stored, is an anatomical extension that narrows into a conical shape before forming the vas deferens. [12] The coiled epididymal duct within the cauda epididymis does not appear to be particularly long, [ 12 ] and so may be limited in its capacity to store sperm in comparison to ...
Each worm has reproductive organs such as vas deferens, testis, uterus, vitelline duct, ovary, and vitellaria. [2] They also have flame cells that function as a kidney and remove waste material. A short duct that opens to the outside on the dorsal surface is composed of four canals on each side, two posterior and two anterior, that come ...